well if it's a large-ish, pipe-shaped airsoft "explosive", you could always excuse it as A) a Demolition charge (for clearing those nasty bunkers, just roll one in and let the fun begin), or Similarly B) an White Phosphorous grenade (
http://www.fas.org/man/dod-101/sys/land/m15.htm), which has also been known to be used for bunker clearing, as well as signaling. Or:
http://www.fas.org/man/dod-101/sys/land/m14-th3.htm
Either way, it sounds like it'd be better to use as a "roll into a tight space to eliminate everything inside" weapon, instead of a "throw as far as you can and possibly hit somone in the head with" weapon. That eliminates the saftey risk greatly (unless you stub your toe on it
) and still makes it usefull